There are many types of vents on the market that allow containers to vent by allowing a small amount of air flow through the vent. Packaging vents are commonly used in providing venting solutions for consumer and industrial liquid cleaners. These liquid cleaners normally contain organic additives and surfactants which lower the surface tension of the liquid thereby promoting wetting and adherence to surfaces.
A further difficulty is that many types of newly developed liquid cleaners additionally have a higher viscosity than previously used. Higher viscosity liquids are preferred as this allows the liquid cleaner to function much better by increasing the adherence and contact time of the liquid to the surface to be cleaned. As a result of both the higher viscosity and the low surface tension, the viscous liquids also have the ability to stick much better to the vents themselves. The vents can therefore easily become clogged by liquid left on the surface of the vent. A further problem arises if the viscous liquid dries on the surface of the vent leaving an impermeable film made up of solid components dissolved in the liquid. The vent may therefore be rendered permanently inoperable with highly viscous liquids.
There is also the issue that many types of liquid cleaners emit small amounts of gaseous substances such as oxygen or chlorine which can lead to containers becoming over-inflated if a vent becomes clogged by a viscous liquid.
Viscous oils are a further type of liquid causing problems in automotive related venting applications. Motor oils, for example, have the ability to stick onto vents for electronic housings thereby preventing air flow and pressure exchange through the vent.
U.S. Pat. No. 5,462,586 relates to an oil- and water-repellent gas-permeable filter which contains a porous filter material that has its internal and external surfaces coated with a compound comprising a first fluoropolymer having a fluorine-containing aliphatic cyclic structure in the main chain and a second fluoropolymer containing polyfluoroalkyl groups. The coating in U.S. Pat. No. 5,462,586 is intended to have substantially no effect on the porosity of the porous filter material. U.S. Pat. No. 5,462,586 is incorporated herein by reference.
It is an object of at least one aspect of the present invention to obviate or mitigate at least one or more of the aforementioned problems.
It is a further object of at least one aspect of the present invention to provide a venting composite that is capable of providing sufficient residual gas flow (e.g. air flow) even after coming into contact with a liquid having both a high viscosity and low surface tension.